Effects of tablet fertilizer on the growth, development and grain yield of maize variety LVN99 cultivated on sloping land were studied in Autumn-Winter crop in Van Yen district, Yen Bai province. The experiment comprised of 10 NK tablet fertilizer treatments, each of which combined with 2 ton of bio-organic fertilizer Song Gianh 90 P2O5 and a control (150 N + 80 P2O5 + 80 K2O/ha, common usage). The growth duration, morphological characteristics, plant height, ear height and leaf number of variety LVN99 were not much different among the treatments, but leaf area index tended to increase with increasing fertilizer doses. All tablet fertilizer treatments also showed a nearly similarity in percentage of root lodging, stalk lodging degree, stem bore, sheath blight (Rhizoctonia solani). There was a significant difference in grain yields among the treatments. The treatment 8 (150 N + 90 K2O) had the highest potential grain yield and harvested grain yield with 72.3quintals/ha and 53.9 quintals/ha, respectively, which were higher than that of the control at a significant level of P0.05. Fertilizer combination: Tablet-chemical fertilizer (150 N + 90 K2O) with 2 ton Song Gianh of bio-organic fertilizer + 90 P2O gave the highest economic efficiency with a benefit of 11,295,000 VND/ha/crop in Autumn-Winter crop.